201122751 六、發明說明： 【發明所屬之技術領域】 θ本發明係關於一種電壓調整電路及其電腦系統，特別 疋一種利用偵測負载電流總量以進行調整USB連接埠之輸 出電壓之電壓調整電路及其電腦系統。 【先前技術】 在=今的電子產品的應用上，許多裝置，例如手機、 相機或是其他的手持式電子裝置，都可使用USB傳輸埠當 作充電的介面。同時目前筆記型電腦或是桌上型電腦都已 經具備咖傳料，啸縣腦雜料電壓皆為固 定的。例如在筆記㈣腦中是由電縣應模組提供Μ或 3.3V之m定電壓給USB傳輸埠，以當作手持式電子裝置電 源訊號。但電源供應模組所提供之5V或3 3v之固定電壓 還必須同時需要提供其他的裝置使用，例如光碟機、硬碟 等等。並且USB傳輸埠通常是電流傳輸的最末端，當· 傳輸琿連接外接式之光碟機或硬碟時，就會需要較大電流 之電源訊號，以符合外接式之光碟機或硬碟所需之壓降7 由於先前技術之電源供應模組所提供電壓皆為5V或 3.3V之固定電壓，並未考慮後端電流負載之大小。當壓降 過低可能造成資料傳輸品質不良，導致傳輸速度變慢，甚 至會因為電壓過低使得USB傳輸埠之訊號完全無法傳送， 使作業系統無法辨認此電子裝置。 、 201122751 為解决上述的缺失，在先前技術中，台灣發明公主 1278737已^接露—種用於細連接埠之限流電路。請^ 考圖1係先前技術之限流電路之硬體架構示意圖。 先前技術之筆記型電腦90具有電源轉換電路92、限流 電路93及USB設備94。筆記型電腦9〇藉由電壓源μ ^ 輸入電源訊號，並經由USB設備94與USB電子裝置％ 電性連接。限流電路93内部具有儲能元件931，例如"電容， 用以提供另一電源訊號之來源。當對USB電子裝置％進 行充電時，限流電路93係進行判斷。當USB電子裝置95 所需之電壓大於參考值時，電源轉換電路92係控制由儲能 元件931以提供USB電子裝置95所需之電壓。 此 利用上述的方式，雖然可以解決供應至USB電子裝置 95之電壓不足的問題，但先前技術之限流電路％會具有 較複雜的電路架構，且必須要增加儲能元件931。如此— 來，會增加許多製造成本。 有鑑於此，因此有必要發明一種電壓調整電路及其電 腦系統’以解決先前技術的缺失。 【發明内容】 本發明之主要目的係在提供一種電壓調整電路及電腦 系統，具有利用偵測負载電流總量以進行調整USB連接埠 之輸出電壓之功能。 本發明之另一主要目的係在提供一種電壓調整之方 201122751 為達成上述之目的’本發明之電壓調整電路，係用於 調整USB連接埠之輸出電壓。電壓調整電路包括電源供應 模組、電流限制模組、電流偵測模組及電流訊號處理模組。 電源供應模組具有電壓調整功能，用以供應電源訊號。電 流限制模組係與電源供應模組電性連接，用以傳輸電源訊 號至USB連接埠，並限制USB連接埠之負載電流總量不超 出設定值。電流偵測模組係與電流限制模組電性連接，用 以偵測USB連接埠之負載電流總量。電流訊號處理模組係 與電流偵測模組電性連接，用以根據負載電流總量調整電 源供應模組之電源訊號。其中若負載電流總量接近設定 值，則電流訊號處理模組控制電源供應模組以增加電源訊 號之電壓值。 本發明之電腦系統包括USB連接埠及電壓調整電路。 電壓調整電路係與USB連接槔電性連接，用以調整usb連 接埠之輸出電壓。電壓調整電路包括電源供應模組、電流 限制模組、電流偵測模組及電流訊號處理模組。電源供應 模組具有電壓調整功能，用以供應電源訊號。電流限制模 組係與電源供應模組電性連接，用以分別傳輸電源訊號至 複數之USB連接埠，並限制複數2USB連接埠之負載電流 總量不超出設定值。電流偵測模組係與電流限制模組電性 連接，用以偵測複數之USB連接埠之負載電流總量。電流 訊號處理模組係與電流偵測模組電性連接，用以根據負載 電流總量調整電源供應模組之電源訊號。其中若負載電流 總量接近設定值，則電流訊號處理模組控制電源供應模組 以增加電源訊號之電壓值。 201122751 〇本發明之電壓調整之方法包括以下步驟：供應電源訊 號至USB連接偵測USB連接埠之負載電流總量；判斷 負載電流總量是否接近狀值；以及若是，麟高電源訊 號之電壓值。 【實施方式】 為讓本發明之上述和其他目的、特徵和優點能更明顯 易懂，下文特舉出本發明之具體實施例，並配合所附圖式， 作詳細說明如下。 請先參考圖2係本發明電腦系統之示意圖。 本發明之電腦系統1係為筆記型電腦或是桌上型電腦 主機，但本發明並不以此為限。電腦系統丨内部包括電壓 調整電路10，USB連接埠20及内部電子裝置70。電腦系 統1可具有單一或是複數之USB連接埠20，使得電腦系統 1可藉由USB連接埠20連接XJSB電子裝置21。USB電子 裝置21可為隨身碟、相機或滑鼠等任何可藉由USB傳輸 協定以傳輸訊號或充電之手持式裝置，但本發明並不以上 述所列舉的裝置為限。電腦系統1還包括了内部電子裝置 70，可為硬碟機或光碟機等裝置’但本發明並不以此為限。 電壓調整電路10用以調整供應至USB連接埠20所需 之輸出電壓。電壓調整電路10包括電源供應模組30、電 流限制模組4 0、電流偵測模組5 0及電流訊號處理模組6 〇， 上述模組之間係彼此電性連接。電源供應模組3 〇星右蔽 調整之功能，能接收市電電源或是電池模組之電源，以 整為得以供應電腦系統1之所需之電源訊號，例如5伏^ 201122751 或3.3伏特之電愿訊號。如此 之USB電子裝置2】命 連接USB連接埠2〇 模組3〇輸出電^號與内部電子裝置7〇即可接收電源供應 電流限制模組40係與 限制USB連接埠2〇少含淑设坪川電性運接，用以 40可利用一金氧 總量。其中電流限制模組 為限。由於USB連接^而成，但本發明並不以此 電子裝置21，若沒= 可要大電流負載之_ 目Φ说 制 連接棒20之負載電流總量， =月匕因為要增加傳輪至㈣電子裝置Μ之電流，導致 必η1之其餘電子元件電流量不足而無法作用。因此 μ須要利用電流限制模組40限制聰連接 流總量、，使其不超出1定值，例如不超出15安培载= 本發明並不以此為限。需注意的是，每個USB連接埠如 可以利用-個電流限制模組40以限制負載電流總量，或是 複數之USB連接琿20同時藉由一個電流限制模組4〇限制 其負載電流總量’ >f旦本發明並不以此為限。 電流偵測模組5〇係與電流限制模組40電性連接，用 以偵測負載電流總量。由於在現有技術中已經揭露許多電 流偵測之方法，並且已經被熟悉此技術之人員所廣泛應 用’故在此不再贅述其方法。 電流訊號處理模組60係同時與電流偵測模組5〇及電 源供應模組30電性連接以形成一迴路。電流偵測模組5〇 债測出負載電流總量之電流值時，電流訊號處理模組6〇係 根據負載電流總量之電流值調整電源供應模組3〇之電源 訊號之電壓值。舉例而言，若當負載電流總量接近設定值 201122751 時，即代表USB電子裝置21需要較大的負載電流，因此 電流訊號處理模組60可控制電源供應模組3〇增加電源訊 號之電壓值。 另一方面，電流訊號處理模組6〇亦可直接設置於電源 供應模組30内，使得電源供應模組3〇可藉由一迴路直接 判斷負載電流總量之電流值。 需注意的是，電流限制模組40還可與寄生電阻41電 性連接，電流偵測模組50係偵測寄生電阻41之電流以決 定電源訊號之電壓值之所需調整值。舉例而言，本發明可 以設定當寄生電阻41之電流增加！安培，則電流訊號處理 模組^控制電源供應模組％提高電源訊號之電壓值〇1 伏特，田寄生電阻41之電流增加2安培’電流訊號處理模 組6〇控制電源供應模組3〇提高電源訊號之電壓值〇 2伏 特。上述之列舉之調整值僅為示意，可依照需求或是寄生 電阻41之阻值來做設定’本發明並不以此為限。 調整:的描f可知，藉由偵測寄生電阻41之電流進行 使得電源供應模組％ 一次提昇太多的電 反值，致輸出功率的浪費與成本的增加。 夕著1參考_3及圖4關於本發明之電壓調整之方法 〜圖。其中圖3係本發明之電壓調整之方法之步 胤^ :圖4係本發明之電壓調整電路之示意圖。 錄日的是’以下雖以具有電壓調整電路10為例 ! 之電壓調整之方法，但本發明之電壓調整之方 法並不以使用在電壓調整電路10為限。 在圖4中係具有第- USB連接琿2〇a、第二腿連接 201122751 皐20b及第—USB連接埠20c ’且分別連接第一電流限制 模組40a、第二電流限制模组働及第三電流限制模組201122751 VI. Description of the invention: [Technical field to which the invention pertains] θ The present invention relates to a voltage adjustment circuit and a computer system thereof, and more particularly to a voltage adjustment circuit for detecting an output voltage of a USB connection using a total amount of load current detected. And its computer system. [Prior Art] In the application of electronic products, many devices, such as mobile phones, cameras, or other handheld electronic devices, can use USB transmission as a charging interface. At the same time, the current notebook computer or desktop computer has been passed on to the coffee, and the voltage of Xiaoxian brains and materials is fixed. For example, in the middle of the note (4), the power supply is provided by the power supply module or the 3.3V constant voltage to the USB transmission port to be used as the power signal of the handheld electronic device. However, the fixed voltage of 5V or 3 3v provided by the power supply module must also be used for other devices, such as CD players, hard disks, and so on. And the USB transmission port is usually the end of the current transmission. When the transmission port is connected to an external CD player or hard disk, a large current power signal is required to meet the requirements of the external optical disk drive or hard disk. Voltage Drop 7 Since the voltage supplied by the prior art power supply module is a fixed voltage of 5V or 3.3V, the back-end current load is not considered. When the voltage drop is too low, the data transmission quality may be poor, resulting in a slow transmission speed. Even if the voltage is too low, the signal transmitted by the USB transmission cannot be transmitted at all, and the operating system cannot recognize the electronic device. , 201122751 In order to solve the above-mentioned shortcomings, in the prior art, Taiwan invented Princess 1278737 has been exposed - a current limiting circuit for fine connection. Please refer to Figure 1 for a schematic diagram of the hardware architecture of the prior art current limiting circuit. The prior art notebook computer 90 has a power conversion circuit 92, a current limiting circuit 93, and a USB device 94. The notebook computer 9 inputs a power signal by a voltage source μ^ and is electrically connected to the USB electronic device via the USB device 94. The current limiting circuit 93 internally has an energy storage component 931, such as a capacitor, to provide a source of another power signal. When the USB electronic device % is charged, the current limiting circuit 93 makes a determination. When the voltage required by the USB electronic device 95 is greater than the reference value, the power conversion circuit 92 controls the voltage required by the energy storage element 931 to provide the USB electronic device 95. In the above manner, although the problem of insufficient voltage supplied to the USB electronic device 95 can be solved, the prior art current limiting circuit % has a complicated circuit structure, and the energy storage element 931 must be added. So — it will add a lot of manufacturing costs. In view of this, it is therefore necessary to invent a voltage regulating circuit and its computer system to solve the deficiencies of the prior art. SUMMARY OF THE INVENTION The main object of the present invention is to provide a voltage adjustment circuit and a computer system having the function of detecting the output voltage of a USB port by detecting the total amount of load current. Another main object of the present invention is to provide a voltage adjustment method. In order to achieve the above object, the voltage adjustment circuit of the present invention is for adjusting the output voltage of the USB port. The voltage adjustment circuit includes a power supply module, a current limiting module, a current detecting module, and a current signal processing module. The power supply module has a voltage adjustment function for supplying power signals. The current limiting module is electrically connected to the power supply module for transmitting the power signal to the USB port and limiting the total load current of the USB port to not exceed the set value. The current detecting module is electrically connected to the current limiting module to detect the total load current of the USB port. The current signal processing module is electrically connected to the current detecting module for adjusting the power signal of the power supply module according to the total load current. If the total load current is close to the set value, the current signal processing module controls the power supply module to increase the voltage value of the power signal. The computer system of the present invention includes a USB port and a voltage adjustment circuit. The voltage adjustment circuit is electrically connected to the USB connection to adjust the output voltage of the usb connection. The voltage adjustment circuit includes a power supply module, a current limiting module, a current detecting module, and a current signal processing module. The power supply module has a voltage adjustment function to supply power signals. The current limiting module is electrically connected to the power supply module for respectively transmitting the power signal to the plurality of USB ports, and limiting the total load current of the plurality of 2 USB ports not exceeding the set value. The current detecting module is electrically connected to the current limiting module for detecting the total load current of the plurality of USB ports. The current signal processing module is electrically connected to the current detecting module for adjusting the power signal of the power supply module according to the total load current. If the total load current is close to the set value, the current signal processing module controls the power supply module to increase the voltage value of the power signal. 201122751 The method for voltage adjustment according to the present invention comprises the steps of: supplying a power signal to a USB connection to detect a total amount of load current of the USB port; determining whether the total load current is close to a value; and if so, a voltage value of the Lin Gao power signal . The above and other objects, features, and advantages of the present invention will become more apparent from the description of the appended claims. Please refer to FIG. 2 for a schematic diagram of the computer system of the present invention. The computer system 1 of the present invention is a notebook computer or a desktop computer host, but the invention is not limited thereto. The computer system 丨 internally includes a voltage adjustment circuit 10, a USB port 20 and an internal electronic device 70. The computer system 1 can have a single or plural USB port 20 so that the computer system 1 can be connected to the XJSB electronic device 21 via the USB port 20. The USB electronic device 21 can be any portable device such as a flash drive, a camera or a mouse that can transmit signals or charge by USB transmission protocol, but the present invention is not limited to the devices listed above. The computer system 1 further includes internal electronic devices 70, which may be devices such as hard disk drives or optical disk drives, but the invention is not limited thereto. The voltage adjustment circuit 10 is used to adjust the output voltage required to supply the USB port 20. The voltage adjustment circuit 10 includes a power supply module 30, a current limiting module 40, a current detecting module 50, and a current signal processing module 6 〇. The modules are electrically connected to each other. Power supply module 3 The function of the right-hand adjustment of the comet can receive the power supply of the mains power supply or the battery module, so as to supply the power signal required by the computer system 1, for example, 5 volts ^ 201122751 or 3.3 volts. May the signal. Such a USB electronic device 2] is connected to a USB port 埠 2 〇 module 3 〇 output electric number and internal electronic device 7 〇 can receive power supply current limit module 40 and limit USB connection 埠 2 〇 less Pingchuan electrical transport, for 40 can use a total amount of gold and oxygen. The current limit module is limited. Since the USB connection is made, the present invention does not use the electronic device 21, and if there is no = a large current load, the total load current of the connecting rod 20 is made, = month due to the increase of the transfer to (4) The current of the electronic device is such that the amount of current of the remaining electronic components of η1 is insufficient to function. Therefore, the current limiting module 40 is required to limit the total amount of the Cong connection flow so as not to exceed a certain value, for example, not exceeding 15 amps. The present invention is not limited thereto. It should be noted that each USB connection can use a current limiting module 40 to limit the total load current, or a plurality of USB ports 20 to limit the total load current by a current limiting module 4 The amount ' > f is not limited to this invention. The current detecting module 5 is electrically connected to the current limiting module 40 for detecting the total load current. Since many methods of current detection have been disclosed in the prior art and have been widely used by those skilled in the art, the method will not be described herein. The current signal processing module 60 is electrically connected to the current detecting module 5 and the power supply module 30 to form a loop. When the current detecting module 5 测 measures the current value of the total load current, the current signal processing module 6 adjusts the voltage value of the power signal of the power supply module 3 according to the current value of the total load current. For example, if the total load current is close to the set value 201122751, which means that the USB electronic device 21 needs a large load current, the current signal processing module 60 can control the power supply module 3 to increase the voltage value of the power signal. . On the other hand, the current signal processing module 6 can also be directly disposed in the power supply module 30, so that the power supply module 3 can directly determine the current value of the total load current through a loop. It should be noted that the current limiting module 40 can also be electrically connected to the parasitic resistance 41. The current detecting module 50 detects the current of the parasitic resistance 41 to determine the required adjustment value of the voltage value of the power signal. For example, the present invention can set the current when the parasitic resistance 41 increases! Ampere, the current signal processing module ^ control power supply module% increase the voltage value of the power signal 〇 1 volt, the field parasitic resistance 41 current increases 2 amps 'current signal processing module 6 〇 control power supply module 3 〇 improve The voltage value of the power signal is 〇2 volts. The above-mentioned adjustment values are merely illustrative and can be set according to the requirements or the resistance of the parasitic resistance 41. The present invention is not limited thereto. According to the adjustment f, it can be seen that by detecting the current of the parasitic resistance 41, the power supply module % raises too much electric inverse value at a time, resulting in waste of output power and cost. At the same time, reference is made to _3 and FIG. 4 regarding the voltage adjustment method of the present invention. FIG. 3 is a step of the voltage adjustment method of the present invention. FIG. 4 is a schematic diagram of the voltage adjustment circuit of the present invention. The following is a method of adjusting the voltage with the voltage adjustment circuit 10 as an example, but the voltage adjustment method of the present invention is not limited to the voltage adjustment circuit 10. In FIG. 4, there is a first USB connection port 2〇a, a second leg connection 201122751 皋20b, and a first USB port 20c', and are respectively connected to the first current limiting module 40a, the second current limiting module, and the first Three current limit module
4〇C。在此實施例中，係以USB電子裝置21與第一 USB 連接埠20a連接為例進行說明，但本發明並不以此為限。 首先進行步驟3〇1 :供應一電源訊號至USB連接埠。 、當USB電子裝置21與第一 USB連接埠20&連接時， 首先電源供應模組3〇係供應電源訊號至第一 USB連接埠 20a 〇 其次進行步驟302 :偵測USB連接埠之一負載電流總 量。 由於第一 USB連接埠20a與USB電子裝置21進行連 結’並且藉由接收到電源訊號而具有電流傳輸。因此第一 電流偵測模組5〇a係偵測流經第一 USB連接埠2〇a之負載 電流。由於在本實施例中只有第一 USB連接埠2〇a連接 USB電子裝置21，因此流經第一 USB連接埠2〇&之負載 電流即視為負載電流總量。 接著進行步驟303:判斷負載電流總量是否接近一設定 值。 在步驟302中得到負載電流總量後，電流訊號處理模 組60係判斷此負載電流總量是否接近設定值，例如1 5安 培’但本發明並不以此為限。 若第一 USB連接埠20a所流經之電流遠小於1.5安 培’則代表USB電子裝置21所造成的電壓降不會對整體 電腦系統1之作用造成影響，因此電流訊號處理模組6〇即 201122751 不動作。 若第一 USB連接埠20a所流經之電流接近或已經為i·5 安培，則代表USB電子裝置21所造成的電壓降可能會對 整體電腦系統1之作用造成影響。 如此一來即進行步驟304:偵測一寄生電阻之電流值。 由於USB電子襞置21之電壓降會對整體電腦系統1 造成影響，因此電流訊號處理模組60必需要控制電源供應4〇C. In this embodiment, the USB electronic device 21 is connected to the first USB port 20a as an example, but the invention is not limited thereto. First, proceed to step 3〇1: Supply a power signal to the USB port. When the USB electronic device 21 is connected to the first USB port 20&, the power supply module 3 first supplies a power signal to the first USB port 20a, and then performs step 302: detecting a load current of the USB port. Total amount. Since the first USB port 20a is connected to the USB electronic device 21 and has a current transmission by receiving a power signal. Therefore, the first current detecting module 5〇a detects the load current flowing through the first USB port 埠2〇a. Since only the first USB port 〇2〇a is connected to the USB electronic device 21 in this embodiment, the load current flowing through the first USB port 埠2〇& is regarded as the total amount of load current. Then, proceed to step 303: determine whether the total load current is close to a set value. After the total amount of load current is obtained in step 302, the current signal processing module 60 determines whether the total amount of the load current is close to a set value, for example, 15 amps, but the invention is not limited thereto. If the current flowing through the first USB port 20a is much less than 1.5 amps, it means that the voltage drop caused by the USB electronic device 21 does not affect the function of the overall computer system 1, so the current signal processing module 6 is 201122751. No action. If the current flowing through the first USB port 20a is close to or has been i. 5 amps, the voltage drop caused by the USB electronic device 21 may affect the overall computer system 1. In this way, step 304 is performed to detect the current value of a parasitic resistance. Since the voltage drop of the USB electronic device 21 affects the overall computer system 1, the current signal processing module 60 must control the power supply.
模組30以提昇電源訊號之電壓值。同時第一電流偵測模組 5〇a要先偵測第一寄生電阻41a之電流值，才能得知電源訊 號所需要的調整值。 '11 最後進行步驟305 :提高電源訊號之電壓值。 當在步驟3〇4巾已經得知冑源訊號所需要的調整值 後’電流訊號處理模M 6〇係控制電源供應模矣且％以 電源訊號之電壓值。如此-來，即增加傳輸至 USB電子裝 置21之電源訊號之電壓值，以 us 到之電壓過低而無法作用。 ^ ^ n 意的是，本發明之電壓調整之方法並不以上 通之步驟次序為限，只要能達成本發明之目的，上述之步 驟次序亦可加以改變。 步 由上述之描述可知，本發明之電壓調整電路⑺不 儲月bTL件來調整輸出到USB連接槔Μ之電壓。並且本 對需求來調整電源訊號之電壓值’而不會造成能量 201122751 綜上所陳，本發明無論就目的、手段及功效，在在均 顯示其迥異於習知技術之特徵，懇請貴審查委員明察， 早曰賜准專利，俾嘉惠社會，實感德便。惟應注意的是， 上述諸多實施例僅係為了便於說明而舉例而已，本發明所 主張之權利範圍自應以申請專利範圍所述為準，而非僅限 於上述實施例。 【圖式簡單說明】 圖1係先前技術之限流電路之硬體架構示意圖。 圖2係本發明之電腦系統之示意圖。 圖3係本發明之電壓調整之方法之步驟流程圖。 圖4係本發明之電壓調整電路之示意圖。 【主要元件符號說明】 先前技術： 筆記型電腦90 電壓源91 電源轉換電路92 限流電路93 儲能元件931 USB設備94 USB電子裝置95 201122751 本發明： 電腦系統1 電壓調整電路10 USB連接埠20 第一 USB連接埠20a 第二USB連接埠20b 第三USB連接埠20c USB電子裝置21 電源供應模組30 電流限制模組40 第一電流限制模組40a 第二電流限制模組40b 第三電流限制模組40c 寄生電阻41 第一寄生電阻41a φ 電流偵測模組50 第一電流偵測模組50a 電流訊號處理模組60 内部電子裝置70 13The module 30 is configured to increase the voltage value of the power signal. At the same time, the first current detecting module 5〇a first detects the current value of the first parasitic resistance 41a to know the adjustment value required for the power signal. '11 Finally, proceed to step 305: increase the voltage value of the power signal. When the adjustment value required for the source signal has been known in step 3, the current signal processing module M 6 controls the power supply mode and the voltage value of the power signal is %. In this way, the voltage value of the power signal transmitted to the USB electronic device 21 is increased, so that the voltage to us is too low to function. ^^ n It is intended that the method of voltage adjustment of the present invention is not limited to the order of the above steps, and the order of the above steps may be changed as long as the object of the present invention can be achieved. Steps As can be seen from the above description, the voltage adjusting circuit (7) of the present invention does not store the monthly bTL to adjust the voltage output to the USB port. And the need to adjust the voltage value of the power signal does not cause the energy 201122751. In summary, the present invention shows its characteristics different from the conventional technology in terms of purpose, means and efficacy. Observing, early granting of patents, and the benefits of the society, the real sense of virtue. It is to be noted that the various embodiments described above are intended to be illustrative only, and the scope of the invention is intended to be limited by the scope of the appended claims. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic diagram of a hardware architecture of a prior art current limiting circuit. 2 is a schematic illustration of a computer system of the present invention. 3 is a flow chart showing the steps of the method of voltage adjustment of the present invention. 4 is a schematic diagram of a voltage regulating circuit of the present invention. [Main component symbol description] Prior art: Notebook computer 90 Voltage source 91 Power conversion circuit 92 Current limiting circuit 93 Energy storage component 931 USB device 94 USB electronic device 95 201122751 The present invention: Computer system 1 Voltage adjustment circuit 10 USB connection 埠 20 First USB port 20a second USB port 20b third USB port 20c USB electronic device 21 power supply module 30 current limiting module 40 first current limiting module 40a second current limiting module 40b third current limiting Module 40c parasitic resistance 41 first parasitic resistance 41a φ current detecting module 50 first current detecting module 50a current signal processing module 60 internal electronic device 70 13